Cheat Sheet (Referencia Técnica)

Tipos de VLAN

VLAN	Descripción
Por defecto	VLAN 1, no se puede borrar ni renombrar
Datos	Tráfico de usuarios
Gestión	Administración (SSH, telnet)
Nativa	En trunk, tramas sin etiqueta (default VLAN 1)
Voz	Teléfonos IP (QoS)

802.1Q: etiqueta de 4 bytes; VID de 12 bits → hasta 4094 VLANs.

Configuración de VLANs

vlan 10
name Ventas
vlan 20
name Systems
vlan 99
name Administrative

interface range f0/1 - 12
switchport mode access
switchport access vlan 10

interface range f0/1 - 24
switchport mode access
switchport access vlan 10

interface range g0/1 - 2
switchport mode trunk
switchport trunk native vlan 99
switchport trunk allowed vlan 10,20,99

VLAN de voz

interface GigabitEthernet0/3
 switchport mode access
 switchport access vlan 10
 switchport voice vlan 100

Direccionamiento del switch (SVI)

interface vlan 1
# ip add sw mask
ip address 192.168.10.1 255.255.255.0
no shutdown
exit

# Switch capa 2 (sin ip routing): gateway obligatorio
ip default-gateway 192.168.99.2

# Switch multicapa: habilita enrutar entre VLANs
ip routing

do copy running-config startup-config

interface vlan 10
# ip add sw mask
ip address 192.168.10.1 255.255.255.0
no shutdown

interface vlan 99
ip address 192.168.99.1 255.255.255.0
no shutdown
exit

# Switch capa 2 (sin ip routing): gateway obligatorio
ip default-gateway 192.168.99.2

# Switch multicapa: habilita enrutar entre VLANs
ip routing

do copy running-config startup-config

Direccionamiento del router (interfaz física)

int g0/1
# ip add gw mask
ip address 192.168.10.1 255.255.255.0
no shutdown

int s0/0/0
ip address 192.168.20.1 255.255.255.252
no shutdown

Subinterfaces (Router-on-a-Stick)

interface g0/1
no shutdown

interface g0/1.10
encapsulation dot1q 10
# ip address GW mask
ip address 192.168.10.1 255.255.255.0

interface g0/1.20
encapsulation dot1q 20
ip address 192.168.20.1 255.255.255.0
exit

# VLAN nativa
interface g0/1
ip address 192.168.99.1 255.255.255.0

Del lado del switch, hacia el router: puerto trunk con las VLANs permitidas.

Verificación switching / direccionamiento

show vlan brief
show interfaces trunk
show ip interface brief
# router
show vlans